Impact absorbing armrest for a motor vehicle

ABSTRACT

A collision absorption system including a collapsing armrest. The armrest is configured to provide support for vertical loading during use. During a side impact collision, the armrest is configured to deform or collapse in a lateral direction. The collapsing armrest may include multiple layers with at least one layer having grooves and channels, or containing cross-ribs, to allow greater deflection in a lateral direction during a side impact collision.

This application is a continuation of U.S. application Ser. No.12/102,475, filed Apr. 14, 2008, which is herein incorporated byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to motor vehicles and inparticular to an impact absorbing armrest for a motor vehicle.

2. Description of Related Art

Osada (U.S. patent application publication number 2007/0236032) teachesan interior trim for an automobile. Osada teaches an interior trim withan armrest projecting from a trim body which supports the armrest. Osadateaches an armrest including a core member, a lower pad layer, an upperpad layer and a skin unit for covering surfaces of the armrest. Osadaalso teaches that a container portion of the core member is providedwith multiple holes arranged in the longitudinal direction of the carbody with spaces interposed in between in a car width direction. Osadateaches that the holes are provided to help deformation or breakage ofthe structure when load in the car width direction is applied to thecore member.

Osada also teaches another embodiment of the armrest that includesbellows. Osada teaches that the bellows have a serrated cross section.Osada teaches that when an external force is applied from a side, thebellows shrink, and can be easily deformed in the car width direction.

Nichols (U.S. Pat. No. 5,445,430) teaches a collapsing armrestconstruction. Nichols teaches a collapsible armrest including a flexibleskin covering, a plastic insert and a foam material. The insert includesa plurality of corrugations so that the shell collapses in the lateraldirection when the armrest is subjected to a side load of the typeexperienced in a side impact collision.

Prior to an impact, the armrest includes an empty chamber that is influid communication with ambient air via a vent. The vent is covered bya rupturable membrane. The chamber is vented to accommodate normalchanges in ambient conditions so that the insert does not expand orcontract in response to ordinary temperature changes. During acollision, the membrane can rupture to avoid pneumatic delay in lateralcollapse of the insert.

Ura et al. (Japanese patent number 11-139232) teaches an armrest for anautomobile obtaining sufficient shock absorbing action and energyabsorbing action by a simple structure. Ura teaches an armrestcomprising a core plate with multiple lateral slits. Ura teaches thatthe lateral slits are used to give flexibility to the armrest to providesufficient shock absorption.

SUMMARY OF THE INVENTION

A deforming armrest for a motor vehicle is disclosed. The invention canbe used in connection with a motor vehicle. The term “motor vehicle” asused throughout the specification and claims refers to any movingvehicle that is capable of carrying one or more human occupants and ispowered by any form of energy. The term motor vehicle includes, but isnot limited to cars, trucks, vans, minivans, SUVs, motorcycles,scooters, boats, personal watercraft, and aircraft.

In one aspect, the invention provides an armrest for a motor vehicle,comprising: a support member attached to a fixed portion of the motorvehicle and configured to provide vertical support for the armrest undera vertical load applied by an arm of an occupant; the support memberincluding a plurality of grooves extending in a direction that isgenerally perpendicular to a lateral direction, the lateral directionbeing a direction between an occupant and the fixed portion of the motorvehicle; the support member further including a plurality of channelsextending in a direction different from the direction perpendicular tothe lateral direction; and where the plurality of channels have analternating configuration.

In another aspect, the plurality of grooves are open on an upper surfaceof the support member.

In another aspect, the plurality of channels are open on the uppersurface of the support member and where the plurality of channels areopen on a lower surface of the support member.

In another aspect, the plurality of channels includes a first set ofchannels extending from a first side of the support member and whereinthe plurality of channels includes a second set of channels extendingfrom a second side of the support member.

In another aspect, the first set of channels is interdigitated with thesecond set of channels.

In another aspect, the channels help facilitate shearing of the supportmember during a side impact.

In another aspect, the invention provides an armrest for a motorvehicle, comprising: a support member attached to a fixed portion of themotor vehicle and configured to provide vertical support for the armrestunder a vertical load applied by an arm of an occupant; the supportmember including a plurality of grooves extending in a direction that isgenerally perpendicular to a lateral direction, the lateral directionbeing a direction between an occupant and the fixed portion of the motorvehicle; the support member further including a plurality of channelsextending in a direction different from the direction perpendicular tothe lateral direction; and where the plurality of channels areconfigured to intersect with the plurality of grooves.

In another aspect, an angle formed between a first channel and a firstgroove is an acute angle.

In another aspect, the grooves extend through a majority of a length ofthe support member.

In another aspect, a first channel has a first end open to a portion ofa first groove.

In another aspect, the support member includes a plurality of holesdisposed on an outer periphery of the support member.

In another aspect, a second channel has a first end open to a portion ofa first hole of the plurality of holes.

In another aspect, the invention provides an armrest for a motorvehicle, comprising: a support member attached to a fixed portion of themotor vehicle and configured to provide vertical support for the armrestunder a vertical load applied by an arm of an occupant; the supportmember including a substantially flat support portion and a ribprojecting away from the substantially flat support portion; the ribextending in a direction that is generally perpendicular to a lateraldirection, the lateral direction being a direction between an occupantand the fixed portion of the motor vehicle; and where the rib isconfigured to substantially reinforce the support member in a verticaldirection and wherein the rib is configured to provide lateraldeformation when a lateral load is applied to the armrest.

In another aspect, the rib is disposed below the substantially flatsupport portion.

In another aspect, the rib includes a hollow cavity that extends througha substantial majority of the rib in the direction perpendicular to thelateral direction.

In another aspect, the rib includes a first leg portion and a second legportion; and wherein the first leg portion and the second leg portionare spaced apart at a first end portion of the rib, and wherein thefirst end portion is associated with the substantially flat supportportion.

In another aspect, the first leg portion and the second leg portion areclosed at a second end portion, the second end portion being disposedfurther away from the substantially flat support portion than the firstend portion.

In another aspect, the first leg portion and the second leg portion arespaced apart at a second end portion, the second end portion beingdisposed further away from the substantially flat support portion thanthe first end portion.

In another aspect, the first leg portion and the second leg portion areconfigured to contact one another at the first end portion of the ribwhen a lateral force is applied to the armrest.

In another aspect, the support member includes a first rib and a secondrib, and where the first rib and the second rib are configured tocontact one another when a lateral force is applied.

Other systems, methods, features and advantages of the invention willbe, or will become, apparent to one of ordinary skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional systems, methods, features andadvantages be included within this description and this summary, bewithin the scope of the invention, and be protected by the followingclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the followingdrawings and description. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention. Moreover, in the figures, likereference numerals designate corresponding parts throughout thedifferent views.

FIG. 1 is an isometric view of a preferred embodiment of a vehicle doorincluding an armrest;

FIG. 2 is an exploded isometric view of preferred embodiment of aportion of an armrest;

FIG. 3 is a cross sectional view of a preferred embodiment of anarmrest;

FIG. 4 is a cross sectional view of a preferred embodiment of an armrestfollowing a lateral impact;

FIG. 5 is an isometric view of a preferred embodiment of a supportmember following a lateral impact;

FIG. 6 is an exploded isometric view of an alternative embodiment of anarmrest;

FIG. 7 is a cross sectional view of an alternative embodiment of anarmrest;

FIG. 8 is a cross sectional view of an alternative embodiment of anarmrest following a lateral impact;

FIG. 9 is a cross sectional view of an alternative embodiment of anarmrest;

FIG. 10 is a cross sectional view of an alternative embodiment of anarmrest following a lateral impact;

FIG. 11 is a cross sectional view of an alternative embodiment of anarmrest following a lateral impact;

FIG. 12 is an exploded isometric view of an alternative embodiment of anarmrest;

FIG. 13 is a cross sectional view of an alternative embodiment of anarmrest;

FIG. 14 is a schematic isometric view of an alternative embodiment of asupport member;

FIG. 15 is a schematic isometric view of an alternative embodiment of asupport member during a lateral impact; and

FIG. 16 is an isometric view of an alternative embodiment of a portionof a support member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates an isometric view of a vehicle door including acollision absorption system, according to one embodiment of theinvention. Preferably, one or more doors of a motor vehicle includeprovisions to prevent or reduce occupant injury in a collision. Whilethe following disclosure teaches an exemplary system and method for usewith a front side passenger, all of the principles, teachings andconcepts are also applicable to any other occupant in a motor vehicle.

In describing directions associated with various components of thecollision absorption system, the terms “lateral direction” as well as“longitudinal direction” may be used. The term “lateral direction” asused throughout this detailed description refers to a direction runningbetween a motor vehicle occupant and a fixed portion of a motor vehiclethat is used to attach a deforming armrest. In some cases, the lateraldirection may run between two sides of a motor vehicle. The term“longitudinal direction” as used throughout this detailed descriptionand in the claims refers to a direction that is perpendicular to thelateral direction. In some cases, the longitudinal direction may runbetween a front of a motor vehicle and a back of a motor vehicle.

In some embodiments, a door may include an outer shell that isassociated with an exterior of a motor vehicle. During a collision, theouter shell may be the first portion of the motor vehicle door that iscontacted. Additionally, in some embodiments, a door may include aninner shell that is associated with an interior of a motor vehicle. Insome cases, the inner shell may be further associated with an interiortrim panel. In a preferred embodiment, a door may include additionalprovisions for absorbing the force of a collision and helping to protecta vehicle occupant.

Referring to FIG. 1, collision absorption system 100 may be associatedwith door 102. Generally, collision absorption system 100 may includevarious components including an armrest, pads and other components.Additionally, door 102 may be associated with additional features notdirectly related to collision absorption system 100. For purposes ofillustration, only some components associated with door 102 areillustrated in the current embodiment. It should be understood, however,that door 102 can also include additional features not illustrated here.

Preferably, door 102 may include inner shell 108 disposed towards aninterior compartment of a motor vehicle. In some embodiments, innershell 108 comprises the steel structure of door 102. In otherembodiments, inner shell 108 could be associated with anotherreinforcing structure. For example, some embodiments include interiortrim panel 110 that is associated with inner shell 108. In some cases,interior trim panel 110 faces an interior compartment of the motorvehicle and can provide a finish to door 102.

In some embodiments, interior trim panel 110 includes armrest 124 thatis mounted to interior trim panel 110. Additionally, interior trim panel110 can include storage pocket 125. In other embodiments, interior trimpanel 110 may include additional provisions, including storagecompartments, vents, electrical window or door lock controls andspeakers as well as other provisions.

Armrest 124 can include handle portion 126 as well as resting portion128. Preferably, handle portion 126 can include a handlebar, recess orother provision that facilitates opening and closing of door 102.Likewise, resting portion 128 can be used to support a hand or arm of avehicle occupant. In particular, resting portion 128 may include restingsurface 130 that provides a generally flat and smooth surface for a handand/or arm. In some embodiments, armrest 124 can include additionalprovisions for storage, including, but not limited to, additionalstorage compartments and cup holders. In this preferred embodiment,armrest 124 includes cup holder 155.

Preferably, an armrest of a motor vehicle is configured to providesupport for vertical loading. In other words, the armrest is preferablyconfigured to support the weight of a hand and/or arm of an occupant.During a side impact collision, however, an armrest may also preferablyinclude provisions for deforming in a lateral direction to reduce theforce of impact between the armrest and any portion of an occupant. In apreferred embodiment, the armrest may be constructed to be weak withrespect to lateral loads that are applied during a side impactcollision.

FIG. 2 illustrates an exploded isometric view of a preferred embodimentof a portion of armrest 124. Throughout the remainder of this detaileddescription, only resting portion 128 of armrest 124 may be illustrated.However, it should be understood that in some embodiments, the sameprinciples discussed for resting portion 128 could also be applied toany other portion of armrest 124, including handle portion 126.

Armrest 124 may include multiple layers. In this embodiment, armrest 124includes outer cover 202. Generally, outer cover 202 may includeprovisions for covering the interior structure of armrest 124. In somecases, outer cover 202 may wrap around the entirety of armrest 124 toprovide a single continuous outer surface for armrest 124. In othercases, outer cover 202 may wrap around only a portion of armrest 124.

Armrest 124 may also include one or more cushioning layers. In thisembodiment, armrest 124 comprises first cushioning layer 204 and secondcushioning layer 206. Generally, first cushioning layer 204 and secondcushioning layer 206 may be configured to provide some flexibility forarmrest 124 as a hand and/or arm are rested on armrest 124. In someembodiments, first cushioning layer 204 may have different deformationcharacteristics from second cushioning layer 206. In other embodiments,first cushioning layer 204 and second cushioning layer 206 could providesimilar deformation characteristics. In a preferred embodiment, eachcushioning layer can be provided with slightly different deformationcharacteristics to fine tune the degree of cushioning provided byarmrest 124.

Armrest 124 can also include additional provisions for supportingvertical loads. In this embodiment, armrest 124 includes support member210. Generally, support member 210 could be any component that isconfigured to provide structure to armrest 124. In some embodiments,support member 210 may be more rigid than a covering layer or acushioning layer. This configuration can allow support member 210 toprovide support for vertical loading.

Generally, each component can be made of any materials known in the art.For example, outer cover 202 could be made of any material including,but not limited to natural leather, synthetic leather, natural fibers,synthetic fibers, cloth, rubber, plastic, metal, wood as well as anyother material. In a preferred embodiment, outer cover 202 could be madeof synthetic leather. Likewise, first cushioning layer 204 and secondcushioning layer 206 could be made of materials including, but notlimited to, foam, rubber, natural or synthetic fibers as well as anyother material. In a preferred embodiment, first cushioning layer 204could be made of a first type of foam. Also, in a preferred embodiment,second cushioning layer 206 could be made of a second type of foam thatis different from the first type of foam. Finally, support member 210could be made of any partially rigid material, including, but notlimited to, metal, plastic, carbon fiber, wood, as well as any othermaterial. In a preferred embodiment, support member 210 may be made of amolded plastic.

Generally, the shape of each component of armrest 124 may vary. In thecurrent embodiment, each component has a substantially similar elongatedshape. However, in other embodiments, the shape of each component couldvary. For example, in an another embodiment, first cushioning layer 204and second cushioning layer 206 could have shapes that are significantlydifferent from the shape of support member 210.

Preferably, the thicknesses of each component may be tuned to adjust thecushioning and support characteristics for armrest 124. In thisembodiment, first cushioning layer 204 has a thickness T2 that issubstantially thinner than thickness T3 associated with secondcushioning layer 206. Also, support member 210 has a thickness T4 thatis approximately similar to thickness T3 of second cushioning layer 206.This arrangement preferably provides for a substantial amount of paddingover support member 210 to prevent armrest 124 from feeling too stiff toan occupant. In other embodiments, however, the thicknesses of each ofthese components could vary. For example, in another embodiment, firstcushioning layer 204 could have a thickness that is substantially equalto or greater than thickness T3 of second cushioning later 206 toprovide increased padding for armrest 124. In addition, outer cover 202has a height H1 that is large enough to allow outer cover 202 to wraparound all other components of armrest 124.

As seen in FIGS. 2-3, armrest 124 may be assembled by combining outercover 202, first cushioning layer 204, second cushioning layer 206 andsupport member 210. In some embodiments, second cushioning layer 206 canbe attached directly to support member 210. Following this, firstcushioning layer 204 can be attached directly to second cushioning layer206. Finally, outer cover 202 can be applied over first cushioning layer204, second cushioning layer 206 and support member 210.

Generally, these components can be attached using any method known inthe art. In some cases, first cushioning layer 204, second cushioninglayer 206 and support member 210 may be attached to one another using anadhesive of some kind. Also, outer cover 202 could be configured to fittightly over first cushioning layer 204, second cushioning layer 206 andsupport member 210. In some cases, outer cover 202 could also be gluedor otherwise attached directly to first cushioning layer 204 andportions of support member 210.

Referring to FIG. 3, an assembled cross sectional view of armrest 124,armrest 124 may include interior cavity 320 disposed beneath supportmember 210. However, in other embodiments, outer cover 202 may beconfigured to fit against support member 210 so that no interior cavity320 is formed. Additionally, in still other embodiments, othercushioning material could be used to fill in portions of interior cavity320.

Preferably, armrest 124 is configured to deflect in a lateral directionwhen a lateral force is applied, such as during an side impactcollision. As previously discussed, outer cover 202, first cushioninglayer 204 and second cushioning layer 206 may be made of materials thatare generally flexible. Therefore, outer cover 202, first cushioninglayer 204 and second cushioning layer 206 may easily deflect in thelateral direction.

In order to provide armrest 124 with significant support for verticalloads, support member 210 is generally constructed of a partially rigidmaterial, such as molded plastic as previously discussed. Preferably,support member 210 is provided with provisions to help weaken supportmember 210 in a lateral direction. In some embodiments, support member210 may include provisions that allow for deflection or bending in alateral direction when a lateral load is applied. In other embodiments,support member 210 may include provisions that allow for permanentdeformation in a lateral direction when a lateral load is applied.

In some embodiments, support member 210 may include provisions to reducethe cross section at some portions. By modifying the cross section atsome portions of support member 210, support member 210 may beconfigured to deflect, deform or otherwise break at portions with areduced cross section as lateral loads are applied. In a preferredembodiment, support member 210 may be configured with a combination ofholes, grooves and channels for modifying the cross section of supportmember 210.

Referring to FIG. 2, support member 210 includes first portion 220.First portion 220 may be a substantially flat support portion that isconfigured to provide support for vertical loads. In some cases, firstportion 220 may be associated with second portion 222. In some cases,second portion 222 may be a sidewall portion that is configured toreinforce first portion 220 at outer periphery 223 of first portion 220.It should be understood that in some embodiments both first portion 220and second portion 222 may also include provisions that may facilitateconnecting armrest 124 to a trim panel or other portion of a door. Forclarity, these connecting provisions are not illustrated in the currentembodiment.

In some embodiments, first portion 220 may include holes or gaps. Inthis embodiment, first portion 220 includes set of holes 226. The numberof holes comprising set of holes 226 may vary. In some embodiments, setof holes 226 may include a single hole. In other embodiments, set ofholes 226 may include two or more holes. In a preferred embodiment, setof holes 226 may include a plurality of holes.

Generally, set of holes 226 may be disposed anywhere within firstportion 220. In this preferred embodiment, set of holes 226 may bedisposed adjacent to outer periphery 223. As seen in FIG. 2, set ofholes 226 may extend from first portion 220 to second portion 222. Withthis arrangement, set of holes 226 may help reduce the cross section offirst portion 220 to help weaken support member 210 in the lateraldirection. In particular, set of holes 226 may help facilitate flexingand cracking at outer periphery 223.

In some embodiments, first portion 220 may include a plurality ofgrooves to help reduce the cross section of support member 210. Firstportion 220 could include any number of grooves. In some embodiments,first portion 220 could include a single groove. In other embodiments,first portion 220 could include two or more grooves. In a preferredembodiment, first portion 220 may include three grooves.

In the current embodiment, first portion 220 may include plurality ofgrooves 230, including first groove 231, second groove 232 and thirdgroove 233, disposed on upper surface 301. Generally, plurality ofgrooves 230 can extend in any direction. For example, grooves can extendin a longitudinal direction, a lateral direction or any directionbetween a longitudinal direction and a lateral direction. In a preferredembodiment, plurality of grooves 230 may extend in a generallylongitudinal direction. In other words, plurality of grooves 230preferably may extend through a length of support member 210. In thiscase, plurality of grooves 230 extend through a majority of the lengthof support member 210.

Referring to FIG. 3, plurality of grooves 230 may reduce the crosssection of first portion 220 at first groove 231, second groove 232 andthird groove 233. For example, first portion 220 has a thickness T5 overa majority of the width of first portion 220. However, beneath firstgrooves 231, second groove 232 and third groove 233, the thickness offirst portion 220 has been reduced to thickness T6. Therefore, firstportion 220 is substantially weaker at portions proximate to firstgroove 231, second groove 232 and third groove 233, which can helpweaken first portion 220 in the lateral direction.

Although the depth of first groove 231, second groove 232 and thirdgroove 233 are substantially similar in the current embodiment, in otherembodiments the depths of each groove could be varied. Furthermore,while the cross sectional shapes of first groove 231, second groove 232and third groove 233 are substantially similar, in other embodiments thecross sections could also vary. By changing the depths of each grooveand varying the cross section, the deformation characteristics of firstportion 220 can be tuned.

In some embodiments, grooves could also be applied to lower surface 302of first portion 220. In the current embodiment, lower surface 302 alsoincludes fourth groove 304. In other embodiments, more than one lowergroove could be used. In still other embodiments, no lower grooves maybe used. By using a combination of grooves on upper surface 301 as wellas lower surface 302 of first portion 220, the deformation properties ofsupport member 210 can be further modified.

In some embodiments, first portion 220 may include other provisions toweaken support member 210 in a lateral direction. For example, firstportion 220 may also include one or more channels. In some cases,channels may be substantially wider than grooves. Furthermore, whereasgrooves may not penetrate completely through first portion 220, channelsmay penetrate through first portion 220 so that each channel is open onlower surface 302 and upper surface 301 of first portion 220. In otherembodiments, however, channels and grooves could have substantiallysimilar widths, depths and or other features.

Referring to FIG. 2, first portion 220 preferably includes plurality ofchannels 240. In this case, plurality of channels 240 comprises firstchannel 241, second channel 242, third channel 243, fourth channel 244and fifth channel 245. Generally, plurality of channels 240 can extendin any direction. For example, plurality of channels 240 could extend ina longitudinal direction, a lateral direction as well as any directionin between the longitudinal and lateral directions. In a preferredembodiment, plurality of channels 240 extend in a direction differentfrom the longitudinal direction. In particular, plurality of channels240 may be disposed generally diagonally across first portion 220.

Preferably, each channel can provide gaps in the cross section ofsupport member 210. For example, fifth channel 245 can be seen in crosssection in FIG. 3, appearing as a wide gap separating first side wall391 and second side wall 392 of first portion 220 by a width W1.Preferably, each of the remaining channels provide gaps throughdifferent portions of support member 210, thereby reducing the lateralstrength.

Generally, the width of each channel can be varied. By varying thewidths of the channels, the overall lateral strength of support member210 can be varied. In some embodiments, the widths of each channel couldhave a value in the range between 0.01 and 5 mm. In other embodiments,the widths of each channel could have a value in the range between 0.5mm and 4 mm. In a preferred embodiment, each channel comprisingplurality of channels 240 may have a value of approximately 3 mm.

In some embodiments, channels and grooves can intersect. In otherembodiments, channels and grooves may not intersect. In still otherembodiments, some channels may intersect with some grooves. In thispreferred embodiment, first channel 241, second channel 242, thirdchannel 243, fourth channel 244 and fifth channel 245 each intersectwith one or more grooves from plurality of grooves 230. Furthermore,each channel generally intersects a groove in a non-perpendicularmanner. For example, first channel 241 is configured to intersect thirdgroove 233 at an angle A. In this embodiment, angle A is an acute anglethat is not a right angle. Preferably, the second channel 242, thirdchannel 243, fourth channel 244 and fifth channel 245 are alsoconfigured to intersect one or more grooves at an acute angle.

Plurality of channels 240 may be disposed in an alternatingconfiguration. For example, first channel 241, second channel 242 andthird channel 243 may form first set of channels 261 that extend fromfirst side 250 of first portion 220 towards central portion 252 of firstportion 220. Likewise, fourth channel 244 and fifth channel 245 may formsecond set of channels 262 that extend from second side 254 of firstportion 220 towards central portion 252. Preferably, first set ofchannels 261 and second set of channels 262 are interdigitated. Withthis interdigitated configuration, plurality of channels 240 canfacilitate shearing during lateral loading to provide a more compactcollapse of armrest 124 and help with shock absorption. Details of thisshearing are discussed in detail below.

In some embodiments, using alternating channels can also help withmaterial flow during molding. In cases where a support member is madewith a molding process, reduced cross sections from channels can reducematerial flow into the mold. Providing alternating channels can create apath for the molding material that can increase the flow. It should beunderstood, however, that this invention is not limited to supportmembers made using such molding techniques.

In some embodiments, channels could also begin or end at grooves and/orholes. For example, first channel 241 preferably has first end 271 thatis open to first hole 281. Also, third channel 243 has first end 272that is open to second hole 282. Additionally, fourth channel 244 hasfirst end 273 that is open to first groove 231. Likewise, fifth channel245 has first end 274 that is open to first groove 231. This preferredarrangement may also help with shearing during lateral impacts.

In some embodiments, second portion 222 may also be associated withgrooves. In this embodiment, second portion 222 includes first sidewallgroove 291 and second sidewall groove 292. Preferably, using grooveswith second portion 222 may help decrease the lateral strength of secondportion 222 while maintaining vertical strength.

In some embodiments, sidewall grooves in second portion 222 can bealigned with channels or holes in first portion 220. In this embodiment,first sidewall groove 291 is preferably aligned with second channel 242.Likewise, second sidewall groove 292 is preferably aligned with secondhole 282 and third channel 243. With this arrangement, the lateral crosssection of support member 210 can be greatly reduced in some regions.

By using both channels and grooves, support member 210 may besignificantly weakened in a lateral direction under an applied lateralforce. In some cases, reducing the cross section in some places usinggrooves and creating gaps in the cross section using channels canprovide weakened portions that are configured for deformation during animpact.

Referring to FIG. 3, as hand 310 and arm 312 are laid on armrest 124they apply a vertical load to armrest 124. At this point, support member210 preferably provides sufficient vertical strength to armrest 124.Furthermore, first cushioning layer 204, second cushioning layer 206 andouter covering 202 preferably help provide a comfortable surface forhand 310 and arm 312.

Referring to FIG. 4, armrest 124 may deform when a lateral force isapplied. In some cases, an outer shell of a door or other portion of amotor vehicle could apply this lateral force during a side impactcollision. As previously discussed, armrest 124 is preferably configuredto deflect, deform or otherwise collapse during lateral loading to helpfacilitate shock absorption and reduce any tendency for injury to anoccupant.

Referring to FIG. 4, as lateral force 402 is applied to armrest 124,outer cover 202, first cushioning layer 204 and second cushioning layer206 may deflect in a lateral direction. In some cases, an excess ofmaterial may create a bulge of these various layers. Furthermore, firstportion 220 of support member 210 has partially collapsed in the lateraldirection, as first side wall 391 and second side wall 392 of fifthchannel 245 have collapsed against one another. Additionally, firstportion 220 has ruptured in regions proximate to first groove 231,second groove 232 and third groove 233 as a result of reduced crosssections in these regions.

FIG. 5 is an enlarged view of a preferred embodiment of support member210 following the application of lateral force 402 as seen in FIG. 4.Some shearing of support member 210 may occur due to the intersection ofplurality of grooves 230 and plurality of channels 240. In thisembodiment, lateral forces have caused first sheared portion 502 andsecond sheared portion 504 to overlap on top of central portion 252.This stacking of first sheared portion 502 and second sheared portion504 may help facilitate lateral contraction as some material slides overtop of adjacent material. This lateral shearing can also help preventupward bulging of first portion 220 during lateral deformation. In somecases, this arrangement may decrease the tendency of pieces of firstportion 220 from being exposed and contacting a vehicle occupant.

A support member may include other provisions for providing increasedvertical support and decreased lateral strength. In some embodiments, asupport member can include one or more ribs that may project away from asubstantially flat support portion of the support member. In some cases,the one or more ribs could extend below the substantially flat supportmember. In other cases, the one or more ribs could extend above thesubstantially flat support member. This ribbed configuration maygenerally provide increased strength for vertical loading and alsoprovide increased deflection or deformation in a lateral direction underlateral loads.

FIGS. 6-15 illustrate alternative embodiments of a support memberprovided with one or more ribs. Referring to FIGS. 6-7, armrest 600 maybe provided with outer cover 602, first cushioning layer 604 and secondcushioning layer 606. Preferably, each of these components can besimilar to outer cover 202, first cushioning layer 204 and secondcushioning layer 206 that have been discussed in the previousembodiment. Armrest 600 preferably also includes support member 610.Preferably, support member 610 is provided with a similar shape, sizeand materials as those discussed for support member 210 of the previousembodiment.

Support member 610 preferably includes substantially flat supportportion 615. Referring to FIG. 6, support member 610 may also beprovided with side wall portion 616 that connects to substantially flatsupport portion 615 at outer periphery 617. In some embodiments, supportmember 610 may also be provided with one or more ribs. In thisembodiment, support member 610 may include first rib 611, second rib 612and third rib 613. Generally, each rib may extend in any direction. Forexample, each rib could extend in a longitudinal direction, a lateraldirection or any direction in between. In this preferred embodiment,first rib 611, second rib 612 and third rib 613 may extend in agenerally longitudinal direction.

Referring to FIG. 7, first rib 611, second rib 612 and third rib 613 mayeach project below lower surface 620 of substantially flat supportportion 615. In the current embodiment, first rib 611, second rib 612and third rib 613 each project a substantially similar distance fromlower surface 620, however in other embodiments the distance each ribprojects could vary.

In some embodiments, ribs may be associated with hollow cavities. Inthis embodiment, first rib 611, second rib 612 and third rib 613 areassociated with first hollow cavity 631, second hollow cavity 632 andthird hollow cavity 633, respectively. In some cases, first hollowcavity 631, second hollow cavity 632 and third hollow cavity 633 mayextend through substantially the entire length of first rib 611, secondrib 612 and third rib 613, respectively. However, in other cases, eachcavity may extend through only a portion of the associated rib.

As seen in FIG. 7, first hollow cavity 631, second hollow cavity 632 andthird hollow cavity 633 may be open at upper surface 650 ofsubstantially flat support portion 615. In particular, first end portion651 of first rib 611 may be open at upper surface 650. Preferably, thefirst end portions of the remaining ribs are also open at upper surface650.

Preferably, first hollow cavity 631, second hollow cavity 632 and thirdhollow cavity 633 are closed at lower surface 620 of substantially flatsupport portion 615. First rib 611 may include first leg portion 641 andsecond leg portion 642 that extend below lower surface 620.Additionally, first rib 611 includes intermediate portion 643 that isdisposed between first leg portion 641 and second leg portion 642. Thisconfiguration preferably provides a closed configuration for first rib611 at second end portion 652 of first rib 611. Preferably, each of theremaining ribs have second end portions that are also closed in asubstantially similar way below lower surface 620.

Referring to FIGS. 7 and 8, first rib 611, second rib 612 and third rib613 may be configured to pinch closed when a lateral force is applied toarmrest 600. As seen in FIG. 7, first leg portion 641 and second legportion 642 of first rib 611 are spaced apart from one another duringnormal use. However, as a lateral force is applied, forces aredistributed through substantially flat support portion 615 in a mannerthat causes first rib 611 to close. As seen in FIG. 8, as a lateralforce is applied, first hollow cavity 631 collapses and first legportion 641 collides with second leg portion 642. Preferably, second rib612 and third rib 613 are configured to pinch closed in a similar mannerto first rib 611. This pinching of first rib 611, second rib 612 andthird rib 613 allows for some shock absorption as well as a controlledreduction in the lateral width of armrest 600.

FIGS. 9 through 11 refer to an alternative embodiment of a deformingarmrest. Referring to FIG. 9, armrest 900 includes substantially similarcomponents to the previous embodiments. For example, armrest 900includes outer cover 902, first cushioning layer 904 and secondcushioning layer 906. Armrest 900 also includes support member 910.

Support member 910 preferably includes substantially flat supportportion 915. In some embodiments, support member 910 may also includefirst rib 911, second rib 912 and third rib 913. Generally, first rib911, second rib 912 and third rib 913 may be substantially similar tothe ribs of the previous embodiment. In particular, first rib 911,second rib 912 and third rib 913 may extend in a generally longitudinaldirection. Also, first rib 911, second rib 912 and third rib 913preferably include first hollow cavity 931, second hollow cavity 932 andthird hollow cavity 933, respectively.

As seen in FIG. 9, first hollow cavity 931, second hollow cavity 932 andthird hollow cavity 933 may be open at upper surface 950 ofsubstantially flat support portion 915. In particular, first end portion951 of first rib 911 may be open at upper surface 950. Preferably, thefirst end portions of second rib 912 and third rib 913 are also open atupper surface 950.

Preferably, first hollow cavity 931, second hollow cavity 932 and thirdhollow cavity 933 are also open at lower surface 920 of substantiallyflat support portion 915. First rib 911 may include first leg portion941 and second leg portion 942 that extend below lower surface 920. In apreferred embodiment, first leg portion 941 and second leg portion 942are spaced apart at second end portion 952 of first rib 911 disposedopposite of first end portion 951. In some embodiments, second rib 912and third rib 913 have second end portions that are also open in asubstantially similar way below lower surface 920.

Referring to FIGS. 9 and 10, first rib 911, second rib 912 and third rib913 may be configured to partially pinch closed when a lateral force isapplied to armrest 900. As seen in FIG. 9, first leg portion 941 andsecond leg portion 942 are spaced apart from one another an averagedistance D1 during normal use. However, as a lateral force is applied,forces are distributed through substantially flat support portion 915 ina manner that causes first rib 911 to partially close. As seen in FIG.10, as a lateral force is applied, first hollow cavity 931 collapses andfirst leg portion 941 partially collides with second leg portion 942. Inthis case, first leg portion 941 and second leg portion 942 are spacedapart by an average distance D2. Preferably, second rib 912 and thirdrib 913 are configured to partially collapse in a similar manner tofirst rib 911. This partial collapse of first rib 911, second rib 912and third rib 913 allows for some shock absorption as well as acontrolled reduction in the lateral width of armrest 900.

FIG. 11 illustrates an alternative embodiment in which first rib 911,second rib 912 and third rib 913 fully collapse under lateral forces. Inparticular, first leg portion 941 and second leg portion 942 of firstrib 911 are configured to contact when lateral loads are applied. Byadjusting the distances between first leg portion 941 and second legportion 942 in a post-loaded condition, the types of shock absorptionand deflection of first rib 911 can be fine tuned. Preferably, thedeformation of second rib 912 and third rib 913 can also be tunedbetween partial collapse and full collapse, thereby facilitatingincreased control of shock absorption and deflection of support member910.

In some embodiments, adjacent ribs could also be configured to contactone another. For example, in an alternative embodiment, the spacingbetween adjacent ribs could be small enough to allow a first leg portionfrom a first rib to contact a second leg portion from a second rib. Inanother embodiment, the length of leg portions could be longer so thateach leg portion could bend and be configured to contact a leg portionof an adjacent rib.

Referring to FIG. 16, in still other embodiments, cross-ribs could beadded to a support member. In some cases, the cross-ribs may bestaggered to help control sideways push strength and crush. In thisalternative embodiment, support member 1610 includes substantially flatsupport portion 1615. In some embodiments, support member 1610 may alsoinclude first rib 1611, second rib 1612 and third rib 1613. Generally,first rib 1611, second rib 1612 and third rib 1613 may be substantiallysimilar to the ribs of the previous embodiment. In particular, first rib1611, second rib 1612 and third rib 1613 may extend in a generallylongitudinal direction. Also, first rib 1611, second rib 1612 and thirdrib 1613 preferably include first hollow cavity 1631, second hollowcavity 1632 and third hollow cavity 1633, respectively.

As seen in FIG. 16, first hollow cavity 1631, second hollow cavity 1632and third hollow cavity 1633 may be open at upper surface 1650 ofsubstantially flat support portion 1615. In particular, first endportion 1651 of first rib 1611 may be open at upper surface 1650.Preferably, the first end portions of second rib 1612 and third rib 1613are also open at upper surface 1650.

Preferably, first hollow cavity 1631, second hollow cavity 1632 andthird hollow cavity 1633 are also open at lower surface 1620 ofsubstantially flat support portion 1615. First rib 1611 may includefirst leg portion 1641 and second leg portion 1642 that extend belowlower surface 1620. In a preferred embodiment, first leg portion 1641and second leg portion 1642 are spaced apart at second end portion 1652of first rib 1611 disposed opposite of first end portion 1651. In someembodiments, second rib 1612 and third rib 1613 have second end portionsthat are also open in a substantially similar way below lower surface1620.

Support member 1610 preferably also includes one or more cross-ribs. Inthis embodiment, support member 1610 may include first cross-rib 1681,second cross-rib 1682 and third cross-rib 1683. Generally, firstcross-rib 1681, second cross-rib 1682 and third cross-rib 1683 areconfigured to extend in a generally lateral direction. For example,first cross-rib 1681 is configured to extend from first leg portion 1641to second leg portion 1642. Likewise, second cross-rib 1682 and thirdcross-rib 1683 may extend across the leg portions of second rib 1612 andthird rib 1613, respectively. As previously discussed, first cross-rib1681, second cross-rib 1682 and third cross-rib 1683 may be staggered.With this arrangement, the lateral deformation of support member 1610can be tuned.

Although the current embodiment includes three cross-ribs, in otherembodiments, any number of cross-ribs may be used. Furthermore, whilethe current embodiment uses staggered cross-ribs, in other embodimentscross-ribs may be configured to extend over the entire lateral width ofa support member. Also, cross-ribs can be used with any type of groovesdiscussed in this detailed description. In particular, the use ofcross-ribs is not limited to grooves that are open on an upper and lowersurface.

FIGS. 12-15 illustrate an alternative embodiment of a deforming armrest.Referring to FIGS. 12-13, armrest 1200 includes covering portion 1202and support member 1204. Although armrest 1200 includes a singlecovering portion 1202 in the current embodiment, in other embodimentscovering portion 1202 could be associated with multiple layers,including one or more cushioning layers. In the current embodiment,covering portion 1202 preferably serves as a cushioning layer andprovides a continuous outer surface for armrest 1200.

Support member 1204 preferably includes substantially flat supportportion 1210. In some embodiments, support member 1204 may also includeone or more ribs. In this preferred embodiment, support member 1204includes first rib 1211, second rib 1212, third rib 1213 and fourth rib1214. Generally, ribs may extend in any direction. For example, ribscould extend in a longitudinal direction, a lateral direction or anydirection in between. In this preferred embodiment, first rib 1211,second rib 1212, third rib 1213 and fourth rib 1214 may extend in agenerally longitudinal direction.

First rib 1211, second rib 1212, third rib 1213 and fourth rib 1214 maypreferably project above substantially flat support portion 1210.Generally, the properties of first rib 1211, second rib 1212, third rib1213 and forth rib 1214 could vary. In some embodiments, the height ofeach rib could vary. In other embodiments, the spacing between adjacentribs could vary. Additionally, in still other embodiments the thicknessof each rib could vary.

Furthermore, the various properties discussed for ribs in the previousembodiments could be applied to first rib 1211, second rib 1212, thirdrib 1213 and fourth rib 1214. For example, in some embodiments, firstrib 1211, second rib 1212, third rib 1213 and fourth rib 1214 could eachinclude a hollow cavity. Also, first rib 1211, second rib 1212, thirdrib 1213 and fourth rib 1214 could include one or more leg portions thatsurround a hollow cavity. In such embodiments, first rib 1211, secondrib 1212, third rib 1213 and fourth rib 1214 could be configured tocollapse in a lateral direction under lateral forces.

In some embodiments, first rib 1211, second rib 1212, third rib 1213 andfourth rib 1214 may be attached to substantially flat support portion1210 using glue or another type of adhesive. In a preferred embodiment,first rib 1211, second rib 1212, third rib 1213 and fourth rib 1214 maybe integrally formed with outer surface 1215 of substantially flatsupport portion 1210. This integral configuration may help provideadditional vertical strength.

FIGS. 14 and 15 illustrate an isometric view of the deformation ofsupport member 1204. For purposes of clarity, covering portion 1202 isnot shown, however it should be understood that covering portion 1202can be configured to deform in a lateral direction with support member1204.

Initially, as seen in FIG. 14, substantially flat support portion 1210has a generally rectangular shape. Also, first rib 1211, second rib1212, third rib 1213 and fourth rib 1214 are all generally straight.Referring to FIG. 15, as lateral force 1502 is applied, support member1204 may bend in a lateral direction. In particular, first end 1504 andsecond end 1506 of substantially flat support portion 1210 may remaingenerally fixed in place. However, under the lateral force, firstlateral side 1508 and second lateral side 1510 may undergo inwardbending. Furthermore, first rib 1211, second rib 1212, third rib 1213and fourth rib 1214 may also bend inwardly. This inward bendingpreferably helps to absorb force applied by lateral force 1502. In somecases, under excessive lateral forces, support member 1204 couldcontinue bending until it breaks. In other cases, support member 1204could permanently deform without breaking.

Generally, a deforming armrest may be disposed on any portion of a motorvehicle to protect vehicle occupants during a front end, rear end orside collision. The embodiments discussed in this detailed descriptionassociate a deforming armrest with a door of a motor vehicle, includingboth front doors and rear doors of a vehicle. In other embodiments,however, a deforming armrest may be disposed within or near otherportions of a motor vehicle associated with a vehicle occupant.Generally, a deforming armrest may be attached to any fixed portion of amotor vehicle, including trim or other fixed portions. For example, adeforming armrest could be attached directly to a seat in someembodiments. In another embodiment, a deforming armrest could beassociated with a trim panel adjacent to a rear seat in a two doorvehicle.

Through the use of the disclosed deforming armrest arrangement, occupantinjury can be reduced by providing an additional energy absorbingstroke.

While various embodiments of the invention have been described, thedescription is intended to be exemplary, rather than limiting and itwill be apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible that are within the scopeof the invention. Accordingly, the invention is not to be restrictedexcept in light of the attached claims and their equivalents. Also,various modifications and changes may be made within the scope of theattached claims.

1. An armrest for a motor vehicle, comprising: a support member attachedto a fixed portion of the motor vehicle and configured to providevertical support for the armrest under a vertical load applied by an armof an occupant, the support member including a substantially flatsupport portion and a rib projecting away from the substantially flatsupport portion, the rib extending in a longitudinal direction that isgenerally perpendicular to a lateral direction, the lateral directionbeing a direction between the occupant and the fixed portion of themotor vehicle, and the rib having a first end portion at thesubstantially flat support portion and a second end portion opposite tothe first end portion, wherein the rib is configured to substantiallyreinforce the support member in a vertical direction and wherein the ribis configured to provide lateral deformation when a lateral force isapplied to the armrest, wherein the rib comprises a first leg portionand a second leg portion projecting away from the substantially flatsupport portion, wherein the first leg portion and the second legportion are spaced apart from each other at the first end portion of therib and at the second end portion of the rib so as to define a hollowcavity that extends through the rib in the longitudinal direction andthat is open at the first end portion and the second end portion of therib, and wherein each of the first and second leg portions has a freeend at the second end portion of the rib.
 2. The armrest according toclaim 1, wherein the first leg portion and the second leg portionconverge toward each other in a direction from the first end portion ofthe rib to the second end portion of the rib.
 3. The armrest accordingto claim 2, wherein the first leg portion and the second leg portiondefine the hollow cavity in a shape of a trapezoidal prism.
 4. Thearmrest according to claim 1, wherein the first leg portion and thesecond leg portion are configured to contact one another at the secondend portion of the rib when the lateral force is applied to the armrest.5. The armrest according to claim 4, wherein the first leg portion andthe second leg portion are configured to contact one another at thefirst end portion of the rib after contacting one another at the secondend portion of the rib, when the lateral force is applied to thearmrest, such that opposing faces of the first leg portion and thesecond leg portion are in contact.
 6. The armrest according to claim 1,wherein the first leg portion and the second leg portion are configuredto contact one another at the second end portion of the rib when alateral force is applied to the armrest, and resist the lateral force ina partially collapsed condition with the first leg portion and thesecond leg portion spaced apart at the first end portion of the rib. 7.The armrest according to claim 1, wherein the rib comprises a first rib,wherein the support member includes a second rib that has a constructionidentical to the first rib and is disposed laterally adjacent to thefirst rib, and wherein the first rib and the second rib are configuredto contact one another when the lateral force is applied.
 8. The armrestaccording to claim 7, wherein the first leg portion of the first ribcontacts the second leg portion of the second rib when the lateral forceis applied.
 9. The armrest according to claim 1, further comprising afirst cross-rib configured to extend in a lateral direction.
 10. Thearmrest according to claim 9, further comprising a second cross-rib in astaggered arrangement with the first cross-rib along the longitudinaldirection.
 11. The armrest according to claim 10, wherein the firstcross-rib has a first upper open edge, a first lower open edge, a secondupper open edge, and a second lower open edge, and wherein the firstupper open edge, the first lower open edge, the second upper open edge,and the second lower open edge are substantially parallel to the lateraldirection.
 12. The armrest according to claim 11, wherein an open sideface of the first cross-rib between the first upper open edge and thefirst lower open edge is shaped as an isosceles trapezoid.
 13. Thearmrest according to claim 10, further comprising a third cross-rib in astaggered arrangement with the first cross-rib and the second cross-ribalong the longitudinal direction, wherein, along the longitudinaldirection, a longitudinal center of the third cross-rib is positionedbetween a longitudinal center of the first cross-rib and a longitudinalcenter of the second cross-rib.
 14. The armrest according to claim 9,wherein the first cross-rib extends over an entire lateral width of thesupport member.
 15. An armrest for a motor vehicle, comprising: asupport member attached to a fixed portion of the motor vehicle andconfigured to provide vertical support for the armrest under a verticalload applied by an arm of an occupant, the support member including asubstantially flat support portion and a rib projecting away from thesubstantially flat support portion, the rib extending in a longitudinaldirection that is generally perpendicular to a lateral direction, thelateral direction being a direction between the occupant and the fixedportion of the motor vehicle, wherein, when viewed in a cross-sectiontaken along a line in the lateral direction, the rib has a first endportion at the substantially flat support portion and a second endportion opposite to the first end portion, the rib comprises a first legportion and a second leg portion projecting away from the substantiallyflat support portion, the first leg portion and the second leg portionare spaced apart from each other at the first end portion of the rib andat the second end portion of the rib so as to define a hollow cavitythat is open at the first end portion and the second end portion of therib, the first leg portion and the second leg portion are unattached atthe second end portion of the rib, and the first leg portion and thesecond leg portion are configured to contact each other at the secondend portion of the rib when a lateral force is applied to the armrest.16. The armrest according to claim 15, further comprising a cross-ribthat connects the first leg portion to the second leg portion along alongitudinal portion of the armrest and spans between the first legportion and the second leg portion when viewed in the cross-section. 17.The armrest according to claim 15, wherein, when viewed in thecross-section, the first leg portion and the second leg portion convergetoward each other in a direction from the first end portion of the ribto the second end portion of the rib.
 18. The armrest according to claim15, wherein the hollow cavity is shaped as a trapezoidal prism.
 19. Thearmrest according to claim 15, wherein the rib comprises a first rib,wherein the support member includes a second rib and a third rib havinga construction identical to the first rib, and wherein the armrestfurther comprises a first cross-rib extending laterally between thefirst leg portion and the second leg portion of the first rib, a secondcross-rib extending laterally between the first leg portion and thesecond leg portion of the second rib, and a third cross-rib extendinglaterally between the first leg portion and the second leg portion ofthe third rib, and wherein the first cross-rib, the second cross-rib,and the third cross-rib are in a staggered arrangement along thelongitudinal direction.
 20. A method of absorbing a lateral forceapplied to a motor vehicle armrest during a collision, the methodcomprising: attaching a support member of the armrest to a fixed portionof the motor vehicle; configuring the support member to provide verticalsupport for the armrest under a vertical load applied by an arm of anoccupant; forming the support member to have a substantially flatsupport portion and a rib projecting away from the substantially flatsupport portion; forming the rib to extend in a longitudinal directionthat is generally perpendicular to a lateral direction, the lateraldirection being a direction between the occupant and the fixed portionof the motor vehicle, with the rib having a first end portion at thesubstantially flat support portion and a second end portion opposite tothe first end portion; forming the rib with a first leg portion and asecond leg portion projecting away from the substantially flat supportportion; spacing the first leg portion and the second leg portion apartfrom each other at the first end portion of the rib and at the secondend portion of the rib so as to define a hollow cavity that extendsthrough a substantial majority of the rib in the longitudinal directionand that is open at the first end portion and the second end portion ofthe rib, wherein each of the first and second leg portions has a freeend at the second end portion of the rib; and absorbing the lateralforce applied to the armrest during the collision by deforming the ribsuch that the first leg portion and the second leg portion contact eachother at the second end portion of the rib.
 21. An armrest for a motorvehicle, comprising: a support member attached to a fixed portion of themotor vehicle and configured to provide vertical support for the armrestunder a vertical load applied by an arm of an occupant, the supportmember including a substantially flat support portion and a ribprojecting away from the substantially flat support portion, the ribextending in a longitudinal direction that is generally perpendicular toa lateral direction, the lateral direction being a direction between theoccupant and the fixed portion of the motor vehicle, and the rib havinga first end portion at the substantially flat support portion and asecond end portion opposite to the first end portion, wherein the rib isconfigured to substantially reinforce the support member in a verticaldirection and wherein the rib is configured to provide lateraldeformation when a lateral force is applied to the armrest, wherein therib comprises a first leg portion and a second leg portion projectingaway from the substantially flat support portion, wherein the first legportion and the second leg portion are spaced apart from each other atthe first end portion of the rib and at the second end portion of therib so as to define a hollow cavity that extends through the rib in thelongitudinal direction and that is open at the first end portion and thesecond end portion of the rib, wherein each of the first and second legportions has a distal end at the second end portion of the rib, andwherein the distal end of the first leg portion is spaced apart from thedistal end of the second leg portion to provide an opening to the hollowcavity at the second end portion of the rib.